Bypass steam injection and production completion system

ABSTRACT

A completion for steam injection and production includes a production tubing connected to a stinger, the production tubing having a continuous conduit extending from a Y-tool to an inverted Y-tool, a downhole steam generator (DSG) having a discharge conduit extending from the DSG to the inverted Y-tool, a bypass conduit extending from the Y-tool to the DSG, and a fuel supply tubing connected to the DSG. An artificial lift device may be incorporated into the completion.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Patent Application No. 61/863,585, filed Aug. 8, 2013 entitled BYPASS STEAM INJECTION AND PRODUCTION COMPLETION SYSTEM which is incorporated herein by reference in its entirety.

BACKGROUND

This section provides background information to facilitate a better understanding of the various aspects of the disclosure. It should be understood that the statements in this section of this document are to be read in this light, and not as admissions of prior art.

Steam injection can be utilized to recover reservoir hydrocarbons. For example, steam may be injected into a subterranean formation through a first well and hydrocarbons produced from adjacent wells. In huff and puff or cyclic operations, steam is injected into a subterranean formation through a wellbore and after a period of time formation fluids are produced from the same well. In cyclic steam injection operations, a steam injection completion may be installed in the wellbore for steam injection and then pulled out of the wellbore when the steam injection is terminated. A production completion is then run into the wellbore when it is desired to place the well on production.

SUMMARY

In accordance to one or more embodiments a completion for steam injection and production includes a production tubing connected to a stinger, the production tubing having a continuous conduit extending from a Y-tool to an inverted Y-tool, a downhole steam generator (DSG) having a discharge conduit extending from the DSG to the inverted Y-tool, a bypass conduit extending from the Y-tool to the DSG, and a fuel supply tubing connected to the DSG. A method includes generating steam at a downhole steam generator that is incorporated in an upper completion in a well, injecting the steam into the formation, terminating the steam generation and producing formation fluid through the upper completion. A well system includes a steam injection and production completion installed in a wellbore and an air supply communicated to a DSG through the production tubing and a bypass conduit during steam generation operations, and the formation fluid is communicated through the production tubing.

The foregoing has outlined some of the features and technical advantages in order that the detailed description of the bypass steam injection and production completion system and methods that follows may be better understood. Additional features and advantages will be described hereinafter which form the subject of the claims of the invention. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of claimed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of bypass sequential steam injection and production completions are described with reference to the following figures. The same numbers are used throughout the figures to reference like features and components. It is emphasized that, in accordance with standard practice in the industry, various features are not necessarily drawn to scale. In fact, the dimensions of various features may be arbitrarily increased or reduced for clarity of discussion.

FIG. 1 illustrates a well system in which embodiments of bypass steam injection and production completions and methods can be utilized.

FIG. 2 illustrates a bypass steam injection and production completion having three tubing strings in accordance with one or more embodiments.

FIG. 3 illustrates a bypass steam injection and production completion having three tubing strings and an artificial lift device in accordance with one or more embodiments.

FIG. 4 illustrates a steam injection and production completion having two tubing strings and an artificial lift device in accordance with one or more embodiments.

FIGS. 5-7 illustrate steam injection and production completions having three tubing strings and an artificial lift device in accordance with one or more embodiments.

FIG. 8 is a diagram of a sequential steam injection to production method in accordance to one or more embodiments.

DETAILED DESCRIPTION

It is to be understood that the following disclosure provides many different embodiments, or examples, for implementing different features of various embodiments. Specific examples of components and arrangements are described below to simplify the disclosure. These are, of course, merely examples and are not intended to be limiting. In addition, the disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.

As used herein, the terms “connect,” “connection,” “connected,” “in connection with,” and “connecting” are used to mean “in direct connection with” or “in connection with via one or more elements”; and the term “set” is used to mean “one element” or “more than one element”. Further, the terms “couple,” “coupling,” “coupled,” “coupled together,” and “coupled with” are used to mean “directly coupled together” or “coupled together via one or more elements”. As used herein, the terms “up” and “down”; “upper” and “lower”; “top” and “bottom”; and other like terms indicating relative positions to a given point or element are utilized to more clearly describe some elements. Commonly, these terms relate to a reference point as the surface from which drilling operations are initiated as being the top point and the total depth being the lowest point, wherein the well (e.g., wellbore, borehole) is vertical, horizontal or slanted relative to the surface. Throughout this disclosure the term “steam” can refer to steam only, or it can refer to steam combined with effluent, such as steam with N₂, CO₂, and other gases entrained together with the steam.

FIG. 1 is an illustration of a well system 5 in which sequential steam injection to production methods and completions, generally denoted by the numeral 10, may be incorporated and utilized. A wellbore 12 extends from a surface 14 to a formation 16 which is in communication with wellbore 12. At least a portion of wellbore 12 may be lined with casing 18. Completion 10 includes a lower completion 20 installed downhole and above formation 16 and an upper completion 22 deployed below wellhead 24 and landed in lower completion 20. In some embodiments the upper and lower completions can be run together as a single completion.

Referring in particular to FIGS. 1 and 2, lower completion 20 may include a packer 26 (i.e. production packer) having a polished bore receptacle (PBR) 28 and a tail pipe 30 extending below packer 26. Lower completion 20 may include an isolation device 32 such as a valve, flow control device, or nipple profile cooperative with a closure member 34 (FIG. 2). Closure member 34 is illustrated in FIG. 2 as a flapper. Isolation device 32 may be mechanically operated between a closed and open position for example by a mechanical shifting tool. In accordance with some embodiments isolation device 32 may be for example a nipple profile and closure member 34 may be a plug. For example the plugs may be coiled tubing, wireline, or slick line deployed. In some embodiments the isolation device 32 is a plug-nipple combination, or a sliding sleeve valve, or another suitable isolation device.

Upper sequential steam-production completion 22 includes a downhole steam generator (DSG) 36 (e.g. combustor) that utilizes a fuel such as natural gas or methane, and air to convert water to steam 74 downhole for injection into formation 16. The steam 74 can be substantially pure steam, or it can have effluent entrained therewith, such as N₂ or CO₂. Upper completion 22 may include a control line 38 extending from the surface to one or more downhole devices. Control line 38 may be a cable, or umbilical, having more than one conduit for transmitting power and or signals. For example, control line 38 may include hydraulic conduits, electrical conductors, optic fibers and the like. Control line 38 is illustrated in FIG. 1 connecting a surface controller 40 with downhole steam generator 36. With additional reference to FIGS. 3-7, control line 38 may be connected for example to sensors, gauges, hydraulic and electrically operated flow control devices, and artificial lift devices (e.g. pumps). Controller 40 may include without limitation electronic circuits, processors, transmitters, receivers and power supplies (i.e. hydraulic, electric), and valves (valve manifolds).

Upper completion 22 is deployed in the wellbore on production tubing 42 extending from the wellhead to a stinger 44 (seal assembly, stabber assembly) which is landed in PBR 28 of lower completion 20. Upper completion 22 includes at a top end a Y-tool 76 that separates or splits a second or bypass conduit 78 from production tubing 42. Bypass conduit 78 is connected back to or combined with production tubing 42 downhole at a lower inverted Y-tool 46. Production tubing 42, also referred to from time to time as first conduit 42, is connected to stinger 44 below inverted Y-tool 46. The section of production tubing 42 located between Y-tool 76 and inverted Y-tool 46 is referred to as continuous conduit 80 from time to time.

Downhole steam generator 36 is connected to a bypass conduit 78 to selectively receive a fluid such as air supply 60 or water supply 64 through production tubing 42. Steam 74, or hot effluent, is discharged from DSG 36 into a section of bypass conduit 78 referred to as discharge conduit 48. Steam discharge 48 of DSG 36 is connected to stinger 44 through inverted Y-tool 46. Inverted Y-tool 46 is illustrated located adjacent to stinger 44 for the purpose of illustrating and describing other features of the sequential steam-production completion.

In accordance with some embodiments a valve 50 (e.g. check valve) is connected within steam discharge 48 between DSG 36 and inverted Y-tool 46 to prevent back flow into DSG 36 from below lower completion 20, e.g. formation fluid, or from production tubing 42. First conduit 42 may include a include a barrier 52, for example a valve or retrievable plug, located in continuous conduit 80 to selectively close the conduit to divert supply fluid to DSG 36 through bypass conduit 78. A plug 53 is illustrated in FIG. 1 landed in barrier 52 blocking production tubing 42 in continuous conduit 80. Continuous conduit 80 can be blocked or closed for example during steam generating and injection operations so that a DSG operational fluid such as water or air can be supplied through production tubing 42 into bypass conduit 78. During production operations production tubing 42 is opened.

Upper completion 22 includes one or more tubing strings, in addition to production tubing 42, connected to DSG 36 to supply operational elements such as fuel, air and water to DSG 36. Upper completion 22 includes a first supply tubing 54, or fuel supply tubing, connected to a fuel supply 56 (e.g. natural gas, methane, hydrogen, etc.) located at the surface. Fuel source 56 may include a compressor. With reference to FIG. 4, water 62 may be supplied from a water supply 64 into wellbore 12 (i.e. annulus) and into inlet 65 of DSG 36. Water supply 64 may include pumps. During steaming operations air supply 60 is communicated through production tubing 42 and bypass conduit 78 to DSG 36. Different fluids can pass through any conduit, such as air through the annulus, or other suitable fluids.

In accordance to some embodiments, for example as illustrated in FIGS. 1-3 and 5-7, a second supply tubing 66 may connect DSG 36 to the surface and one or the other of water supply 64 or air supply 60. During steaming operations water may be supplied to DSG 36 via second supply tubing 66 and air may be supplied to DSG 36 through production tubing 42 and bypass conduit 78 or air may be supplied via supply tubing 66 and water may be supplied through production tubing 42. Examples of method of sequential steam injection and production will be described with reference to supplying air via production tubing 42 and bypass conduit 78 and water via second supply tubing 66.

In accordance to one or more embodiments, upper completion 22 may include an artificial lift device 68 for example as illustrated in FIGS. 3-7. Artificial lift device 68 may be without limitation an electric submersible pump (ESP), positive displacement pump, gas lift device (e.g. valve), jet pump, or piston. Artificial lift devices 68 may be incorporated for example in continuous conduit 80 of production tubing 42 between upper Y-tool 76 and inverted Y-tool 46.

FIGS. 3 and 4 illustrate artificial lift devices 68 such as electric submersible pumps and positive displacement pumps. FIG. 5 illustrates sequential steam-production completion utilizing a jet pump type of artificial lift device 68. For example, a power fluid (e.g. water) from water supply tubing 66 can be directed for example via controller 40 (FIG. 1) and control valve 70 to artificial lift device 68. Controller 40 may manipulate the application of power fluid to operate the jet pump 68. The lift device 68 can be a piston or other positive displacement pump driven by the power fluid.

FIG. 6 illustrates a completion 22 utilizing artificial lift device 68 as a thermal jet pump. For example, fuel and water can be supplied to DSG 36 (i.e. combustor) and the combustor operated to produce a hot effluent 74. The hot effluent may not be steam. A control valve 70 located for example in discharge 48 may be operated to direct the hot effluent into artificial lift device 68 (e.g. valve). The hot effluent heats the produced fluid to reduce viscosity and reduce the gravity (gas lift mechanism) and impart momentum to the produced fluid.

FIG. 7 illustrates artificial lift device 68 utilized as a gas lift device (valve) coupled for example to fuel supply tubing 54 through a control valve 70. During production operations, gas (e.g. natural gas) from fuel supply 56 (FIG. 1) may be directed from fuel supply tubing 54 into gas lift device 68 to reduce the gravity of the formation fluid 72 in production tubing 42 to aid production to the surface. In some embodiments the hot effluent is directed down through the discharge 48 without need of an artificial lift device downhole. The hot effluent flows downward from the DSG 36 through the Y-tool and into the production tubing 42.

FIG. 8 schematically illustrates a sequential steam-production method 100 in accordance to one or more embodiments. With additional reference to FIGS. 1-7, sequential steam-production completion 10 is deployed 110 in wellbore 24. As will be understood by those skilled in the art with benefit of this disclosure, completion 10 can be utilized for cyclical steam stimulation (CSS) methods. Lower completion 20 is landed and set in wellbore 12. Upper completion 22 is then deployed in the wellbore and stinger 44 is landed in the polished bore receptacle 28 of packer 26. An isolation device 32 in lower completion 20 may be utilized to isolate formation 16 from the upper portion of the wellbore as desired. Downhole steam generator (combustor) 36 is fluidly coupled with a water supply, fuel supply and air supply.

Fuel 56, air 60, and water 62 are supplied 120 to DSG 36. Controller 40 may be utilized to control the supply of fuel, air and water to DSG 36 and operate DSG 36 to generate 130 steam 74. Fuel supply 56 is connected for example to DSG 36 through a first supply tubing 54. Water supply 64 may be communicated to wellbore 12 and to DSG 36 through an inlet 65 (FIG. 4) open to the wellbore. Water supply 64 may be connected to DSG 36 through a second supply tubing 66. In accordance to one or more embodiments, air supply 60 is communicated to DSG 36 through production tubing 42 and bypass conduit 78. For example, barrier 52 is closed directing air supply 60 from production tubing 42 into bypass conduit 78 and DSG 36. Barrier 52 is shown closed in FIG. 1 with a plug 53 (dashed lines) deployed and landed at barrier 52 (e.g. nipple profile). In accordance with some embodiments barrier 52 may be a valve.

DSG 36 is operated to combust the supplied air and fuel and to generate 130 steam 74. Steam 74 is exhausted through discharge 48, valve 50 and through lower completion 20 and is injected into formation 16.

When steaming operations are completed DSG 36 may be shut-down 140 and the air, water, and fuel supplies to DSG 36 closed. In accordance to some embodiments, the well or formation 16 may be suspended for a period of time, i.e. soak period, before placing the well on production. During the soak period the production tubing may be closed by barrier 52 and valve 50 isolates DSG 36 from the back flow of steam 74 and formation fluid 72. In other embodiments, the isolation valve 32 (see FIG. 2) can be used to direct fluid flow upward through production tubing 42. In accordance to embodiments, upper completion 22 is not pulled out of the wellbore while the well soaks.

The well is placed 150 on production for example by opening barrier 52 and allowing formation fluid 72 to produce to the surface. In the FIG. 1 depiction, barrier 52 may be opened by intervening for example through wellhead 24 and removing plug 53 for example via slick line, wireline or coiled tubing. Once barrier 52 is open, formation fluid 72 may be produced through lower completion 20 into production tubing 42 and to surface 14.

In accordance to some embodiments, artificial lift (i.e. secondary lift) may be desired to produce formation fluid 72 to the surface. Artificial lift devices 68 incorporated in completion 22 may be operated 160 to aid in producing formation fluid 72 to the surface. In accordance to some embodiments, artificial lift device 68 may be a operated via control line 38. In some embodiments, artificial lift device 68 is a gas lift valve. Gas, for example fuel supply 56, is directed from fuel tubing 54 into production tubing 42 through gas lift valve 68. In accordance to some embodiments, artificial lift device 68 is a jet pump. Power fluid, i.e. water supply 64, is directed to production tubing 42 to actuate jet pump 68. In accordance to some embodiments, DSG 36 may be operated to produce a hot effluent that may be directed from steam generator discharge 48 to artificial lift device 68. The hot effluent may be diverted from discharge 48 between DSG 36 and valve 50.

The foregoing outlines features of several embodiments of bypass steam injection to production completions and methods so that those skilled in the art may better understand the aspects of the disclosure. Those skilled in the art should appreciate that they may readily use the disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the disclosure, and that they may make various changes, substitutions and alterations herein without departing from the spirit and scope of the disclosure. The scope of the invention should be determined only by the language of the claims that follow. The term “comprising” within the claims is intended to mean “including at least” such that the recited listing of elements in a claim are an open group. The terms “a,” “an” and other singular terms are intended to include the plural forms thereof unless specifically excluded. 

What is claimed is:
 1. A method, comprising: generating steam at a downhole steam generator (DSG) incorporated in an upper completion that is deployed in a wellbore; injecting the steam into a formation located below a lower completion deployed in the wellbore; terminating steam generation; and producing formation fluid from the formation through the upper completion after the terminating steam generation.
 2. The method of claim 1, wherein the upper completion is not pulled out of the wellbore between the terminating steam generation and the producing.
 3. The method of claim 1, wherein the producing comprises operating an artificial lift device incorporated in the upper completion.
 4. The method of claim 1, wherein the producing comprises operating an artificial lift device incorporated in the upper completion, the artificial lift device comprising one selected from a pump, a gas lift device, and a jet pump.
 5. The method of claim 1, wherein: the upper completion is not pulled out of the wellbore between the terminating steam generation and the producing; and the producing comprises operating an artificial lift device incorporated in the upper completion.
 6. The method of claim 1, wherein the upper completion comprises: a production tubing extending from the surface to a stinger landed in the lower completion, the production tubing having a continuous conduit extending from a Y-tool to an inverted Y-tool; a bypass conduit extending from the Y-tool to the DSG; a discharge conduit extending from the DSG to the inverted Y-tool; and a fuel supply tubing communicating a fuel supply to the DSG.
 7. The method of claim 6, wherein the generating steam comprises: communicating a water supply to the DSG; communicating the fuel supply to the DSG through the fuel supply tubing; and communicating an air supply to the DSG through the production tubing and the bypass conduit.
 8. The method of claim 7, wherein the water supply is communicated to the DSG through a water supply tubing.
 9. The method of claim 6, wherein: the generating steam comprises: communicating a water supply to the DSG; communicating the fuel supply to the DSG through the fuel supply tubing; and communicating an air supply to the DSG through the production tubing and the bypass conduit; and the producing comprises: communicating formation fluid from below the lower completion through the production tubing.
 10. The method of claim 1, wherein the upper completion comprises: a production tubing extending from the surface to a stinger landed in the lower completion, the production tubing having a continuous conduit extending from a Y-tool to an inverted Y-tool; a bypass conduit extending from the Y-tool to the DSG; a discharge conduit extending from the DSG to the inverted Y-tool; an artificial lift device incorporated in the continuous conduit; and a fuel supply tubing communicating a fuel supply to the DSG.
 11. The method of claim 10, wherein: the generating steam comprises: communicating a water supply to the DSG; communicating the fuel supply to the DSG through the fuel supply tubing; and communicating an air supply to the DSG through the production tubing and the bypass conduit; and the producing comprises: communicating formation fluid from below the lower completion through the production tubing; and operating the artificial lift device.
 12. A completion for steam injection and production, the completion comprising: a production tubing connected to a stinger, the production tubing having a continuous conduit extending from a Y-tool to an inverted Y-tool; a downhole steam generator (DSG) having a discharge conduit extending from the DSG to the inverted Y-tool; a bypass conduit extending from the Y-tool to the DSG; and a fuel supply tubing connected to the DSG.
 13. The completion of claim 12, comprising a water supply tubing connected to the DSG.
 14. The completion of claim 13, comprising: a jet pump incorporated in the continuous conduit; and a control valve coupled between the water supply tubing and the production tubing to actuate the jet pump.
 15. The completion of claim 12, comprising an artificial lift device incorporated in the continuous conduit.
 16. The completion of claim 12, comprising: a barrier located in the continuous conduit; and a one-way valve located in the discharge conduit of the DSG allowing one-way flow from the DSG.
 17. A well system, comprising: a stinger landed in a packer located in a wellbore between a formation and a surface; a production tubing extending from the surface to the stinger, the production tubing having a continuous conduit extending from a Y-tool to an inverted Y-tool; a downhole steam generator (DSG) having a discharge conduit extending from the DSG to the inverted Y-tool; a bypass conduit extending from the Y-tool to the DSG; a fuel supply tubing communicating a fuel supply to the DSG; a water supply in communication with the DSG; and a surface air supply in communication with the DSG through the production tubing and the bypass conduit.
 18. The well system of claim 17, wherein the water supply is in communication with the DSG through a water supply tubing.
 19. The well system of claim 17, comprising an artificial lift device incorporated in the continuous conduit.
 20. The well system of claim 17, comprising: a barrier located in the continuous conduit; and a one-way valve located in the discharge conduit of the DSG allowing one-way flow from the DSG. 